The present invention relates generally to a machine tool, such as a lathe, milling machine or boring machine and the like, and, more particularly, relates to a machine tool having an improved mechanism for driving a main spindle.
Generally speaking, conventional machine tools have main spindles to which a rotational driving force is transmitted from main spindle driving electric motors fixed on bases on the like through suitable transmitting mechanisms, such as, for example, belt transmissions including belts and pulleys, gear transmissions or the like. Because transmitting mechanisms are necessary for fulfilling the above purpose, the construction of such conventional machine tools becomes complicated thereby increasing the cost thereof. Additionally, it is difficult to increase stability in the rotational speeds of the main spindles, due to slippage caused in the transmitting mechanisms or in the backlash of gear trains.
It is a principal object of this invention to provide a machine tool which does not have the above-mentioned defects.
It is a further object of this invention to provide a machine tool wherein a main spindle thereof is rotated at stable rotational speeds.
It is a still further object of this invention to provide a machine tool which has fewer parts than those of conventional machine tools, and which thus costs less to construct.